seccomp/cache: Report cache data through /proc/pid/seccomp_cache

Currently the kernel does not provide an infrastructure to translate
architecture numbers to a human-readable name. Translating sysca

seccomp/cache: Report cache data through /proc/pid/seccomp_cache

Currently the kernel does not provide an infrastructure to translate
architecture numbers to a human-readable name. Translating syscall
numbers to syscall names is possible through FTRACE_SYSCALL
infrastructure but it does not provide support for compat syscalls.

This will create a file for each PID as /proc/pid/seccomp_cache.
The file will be empty when no seccomp filters are loaded, or be
in the format of:
<arch name> <decimal syscall number> <ALLOW | FILTER>
where ALLOW means the cache is guaranteed to allow the syscall,
and filter means the cache will pass the syscall to the BPF filter.

For the docker default profile on x86_64 it looks like:
x86_64 0 ALLOW
x86_64 1 ALLOW
x86_64 2 ALLOW
x86_64 3 ALLOW
[...]
x86_64 132 ALLOW
x86_64 133 ALLOW
x86_64 134 FILTER
x86_64 135 FILTER
x86_64 136 FILTER
x86_64 137 ALLOW
x86_64 138 ALLOW
x86_64 139 FILTER
x86_64 140 ALLOW
x86_64 141 ALLOW
[...]

This file is guarded by CONFIG_SECCOMP_CACHE_DEBUG with a default
of N because I think certain users of seccomp might not want the
application to know which syscalls are definitely usable. For
the same reason, it is also guarded by CAP_SYS_ADMIN.

Suggested-by: Jann Horn <jannh@google.com>
Link: https://lore.kernel.org/lkml/CAG48ez3Ofqp4crXGksLmZY6=fGrF_tWyUCg7PBkAetvbbOPeOA@mail.gmail.com/
Signed-off-by: YiFei Zhu <yifeifz2@illinois.edu>
Signed-off-by: Kees Cook <keescook@chromium.org>
Link: https://lore.kernel.org/r/94e663fa53136f5a11f432c661794d1ee7060779.1605101222.git.yifeifz2@illinois.edu

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context_tracking: Introduce HAVE_CONTEXT_TRACKING_OFFSTACK

Historically, context tracking had to deal with fragile entry code path,
ie: before user_exit() is called and after user_enter() is called,

context_tracking: Introduce HAVE_CONTEXT_TRACKING_OFFSTACK

Historically, context tracking had to deal with fragile entry code path,
ie: before user_exit() is called and after user_enter() is called, in
case some of those spots would call schedule() or use RCU. On such
cases, the site had to be protected between exception_enter() and
exception_exit() that save the context tracking state in the task stack.

Such sleepable fragile code path had many different origins: tracing,
exceptions, early or late calls to context tracking on syscalls...

Aside of that not being pretty, saving the context tracking state on
the task stack forces us to run context tracking on all CPUs, including
housekeepers, and prevents us to completely shutdown nohz_full at
runtime on a CPU in the future as context tracking and its overhead
would still need to run system wide.

Now thanks to the extensive efforts to sanitize x86 entry code, those
conditions have been removed and we can now get rid of these workarounds
in this architecture.

Create a Kconfig feature to express this achievement.

Signed-off-by: Frederic Weisbecker <frederic@kernel.org>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Link: https://lkml.kernel.org/r/20201117151637.259084-2-frederic@kernel.org

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fanotify: Fix sys_fanotify_mark() on native x86-32

commit 2ca408d9c749c32288bc28725f9f12ba30299e8f upstream.

Commit

121b32a58a3a ("x86/entry/32: Use IA32-specific wrappers for syscalls taking 64

fanotify: Fix sys_fanotify_mark() on native x86-32

commit 2ca408d9c749c32288bc28725f9f12ba30299e8f upstream.

Commit

121b32a58a3a ("x86/entry/32: Use IA32-specific wrappers for syscalls taking 64-bit arguments")

converted native x86-32 which take 64-bit arguments to use the
compat handlers to allow conversion to passing args via pt_regs.
sys_fanotify_mark() was however missed, as it has a general compat
handler. Add a config option that will use the syscall wrapper that
takes the split args for native 32-bit.

[ bp: Fix typo in Kconfig help text. ]

Fixes: 121b32a58a3a ("x86/entry/32: Use IA32-specific wrappers for syscalls taking 64-bit arguments")
Reported-by: Paweł Jasiak <pawel@jasiak.xyz>
Signed-off-by: Brian Gerst <brgerst@gmail.com>
Signed-off-by: Borislav Petkov <bp@suse.de>
Acked-by: Jan Kara <jack@suse.cz>
Acked-by: Andy Lutomirski <luto@kernel.org>
Link: https://lkml.kernel.org/r/20201130223059.101286-1-brgerst@gmail.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

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Revert: "ring-buffer: Remove HAVE_64BIT_ALIGNED_ACCESS"

commit adab66b71abfe206a020f11e561f4df41f0b2aba upstream.

It was believed that metag was the only architecture that required the ring
buffer

Revert: "ring-buffer: Remove HAVE_64BIT_ALIGNED_ACCESS"

commit adab66b71abfe206a020f11e561f4df41f0b2aba upstream.

It was believed that metag was the only architecture that required the ring
buffer to keep 8 byte words aligned on 8 byte architectures, and with its
removal, it was assumed that the ring buffer code did not need to handle
this case. It appears that sparc64 also requires this.

The following was reported on a sparc64 boot up:

kernel: futex hash table entries: 65536 (order: 9, 4194304 bytes, linear)
kernel: Running postponed tracer tests:
kernel: Testing tracer function:
kernel: Kernel unaligned access at TPC[552a20] trace_function+0x40/0x140
kernel: Kernel unaligned access at TPC[552a24] trace_function+0x44/0x140
kernel: Kernel unaligned access at TPC[552a20] trace_function+0x40/0x140
kernel: Kernel unaligned access at TPC[552a24] trace_function+0x44/0x140
kernel: Kernel unaligned access at TPC[552a20] trace_function+0x40/0x140
kernel: PASSED

Need to put back the 64BIT aligned code for the ring buffer.

Link: https://lore.kernel.org/r/CADxRZqzXQRYgKc=y-KV=S_yHL+Y8Ay2mh5ezeZUnpRvg+syWKw@mail.gmail.com

Cc: stable@vger.kernel.org
Fixes: 86b3de60a0b6 ("ring-buffer: Remove HAVE_64BIT_ALIGNED_ACCESS")
Reported-by: Anatoly Pugachev <matorola@gmail.com>
Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

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kbuild: Hoist '--orphan-handling' into Kconfig

Currently, '--orphan-handling=warn' is spread out across four different
architectures in their respective Makefiles, which makes it a little
unruly to

kbuild: Hoist '--orphan-handling' into Kconfig

Currently, '--orphan-handling=warn' is spread out across four different
architectures in their respective Makefiles, which makes it a little
unruly to deal with in case it needs to be disabled for a specific
linker version (in this case, ld.lld 10.0.1).

To make it easier to control this, hoist this warning into Kconfig and
the main Makefile so that disabling it is simpler, as the warning will
only be enabled in a couple places (main Makefile and a couple of
compressed boot folders that blow away LDFLAGS_vmlinx) and making it
conditional is easier due to Kconfig syntax. One small additional
benefit of this is saving a call to ld-option on incremental builds
because we will have already evaluated it for CONFIG_LD_ORPHAN_WARN.

To keep the list of supported architectures the same, introduce
CONFIG_ARCH_WANT_LD_ORPHAN_WARN, which an architecture can select to
gain this automatically after all of the sections are specified and size
asserted. A special thanks to Kees Cook for the help text on this
config.

Link: https://github.com/ClangBuiltLinux/linux/issues/1187
Acked-by: Kees Cook <keescook@chromium.org>
Acked-by: Michael Ellerman <mpe@ellerman.id.au> (powerpc)
Reviewed-by: Nick Desaulniers <ndesaulniers@google.com>
Tested-by: Nick Desaulniers <ndesaulniers@google.com>
Signed-off-by: Nathan Chancellor <natechancellor@gmail.com>
Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>

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seccomp: Move config option SECCOMP to arch/Kconfig

In order to make adding configurable features into seccomp easier,
it's better to have the options at one single location, considering
especially

seccomp: Move config option SECCOMP to arch/Kconfig

In order to make adding configurable features into seccomp easier,
it's better to have the options at one single location, considering
especially that the bulk of seccomp code is arch-independent. An quick
look also show that many SECCOMP descriptions are outdated; they talk
about /proc rather than prctl.

As a result of moving the config option and keeping it default on,
architectures arm, arm64, csky, riscv, sh, and xtensa did not have SECCOMP
on by default prior to this and SECCOMP will be default in this change.

Architectures microblaze, mips, powerpc, s390, sh, and sparc have an
outdated depend on PROC_FS and this dependency is removed in this change.

Suggested-by: Jann Horn <jannh@google.com>
Link: https://lore.kernel.org/lkml/CAG48ez1YWz9cnp08UZgeieYRhHdqh-ch7aNwc4JRBnGyrmgfMg@mail.gmail.com/
Signed-off-by: YiFei Zhu <yifeifz2@illinois.edu>
[kees: added HAVE_ARCH_SECCOMP help text, tweaked wording]
Signed-off-by: Kees Cook <keescook@chromium.org>
Link: https://lore.kernel.org/r/9ede6ef35c847e58d61e476c6a39540520066613.1600951211.git.yifeifz2@illinois.edu

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mm: fix exec activate_mm vs TLB shootdown and lazy tlb switching race

Reading and modifying current->mm and current->active_mm and switching
mm should be done with irqs off, to prevent races seeing

mm: fix exec activate_mm vs TLB shootdown and lazy tlb switching race

Reading and modifying current->mm and current->active_mm and switching
mm should be done with irqs off, to prevent races seeing an intermediate
state.

This is similar to commit 38cf307c1f20 ("mm: fix kthread_use_mm() vs TLB
invalidate"). At exec-time when the new mm is activated, the old one
should usually be single-threaded and no longer used, unless something
else is holding an mm_users reference (which may be possible).

Absent other mm_users, there is also a race with preemption and lazy tlb
switching. Consider the kernel_execve case where the current thread is
using a lazy tlb active mm:

call_usermodehelper()
kernel_execve()
old_mm = current->mm;
active_mm = current->active_mm;
*** preempt *** --------------------> schedule()
prev->active_mm = NULL;
mmdrop(prev active_mm);
...
<-------------------- schedule()
current->mm = mm;
current->active_mm = mm;
if (!old_mm)
mmdrop(active_mm);

If we switch back to the kernel thread from a different mm, there is a
double free of the old active_mm, and a missing free of the new one.

Closing this race only requires interrupts to be disabled while ->mm
and ->active_mm are being switched, but the TLB problem requires also
holding interrupts off over activate_mm. Unfortunately not all archs
can do that yet, e.g., arm defers the switch if irqs are disabled and
expects finish_arch_post_lock_switch() to be called to complete the
flush; um takes a blocking lock in activate_mm().

So as a first step, disable interrupts across the mm/active_mm updates
to close the lazy tlb preempt race, and provide an arch option to
extend that to activate_mm which allows architectures doing IPI based
TLB shootdowns to close the second race.

This is a bit ugly, but in the interest of fixing the bug and backporting
before all architectures are converted this is a compromise.

Signed-off-by: Nicholas Piggin <npiggin@gmail.com>
Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/20200914045219.3736466-2-npiggin@gmail.com

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uaccess: add infrastructure for kernel builds with set_fs()

Add a CONFIG_SET_FS option that is selected by architecturess that
implement set_fs, which is all of them initially. If the option is not

uaccess: add infrastructure for kernel builds with set_fs()

Add a CONFIG_SET_FS option that is selected by architecturess that
implement set_fs, which is all of them initially. If the option is not
set stubs for routines related to overriding the address space are
provided so that architectures can start to opt out of providing set_fs.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Kees Cook <keescook@chromium.org>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>

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static_call: Add simple self-test for static calls

Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Link: https://lore.kernel.org/r/20200818

static_call: Add simple self-test for static calls

Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Link: https://lore.kernel.org/r/20200818135804.922581202@infradead.org

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static_call: Add inline static call infrastructure

Add infrastructure for an arch-specific CONFIG_HAVE_STATIC_CALL_INLINE
option, which is a faster version of CONFIG_HAVE_STATIC_CALL. At
runtime, t

static_call: Add inline static call infrastructure

Add infrastructure for an arch-specific CONFIG_HAVE_STATIC_CALL_INLINE
option, which is a faster version of CONFIG_HAVE_STATIC_CALL. At
runtime, the static call sites are patched directly, rather than using
the out-of-line trampolines.

Compared to out-of-line static calls, the performance benefits are more
modest, but still measurable. Steven Rostedt did some tracepoint
measurements:

https://lkml.kernel.org/r/20181126155405.72b4f718@gandalf.local.home

This code is heavily inspired by the jump label code (aka "static
jumps"), as some of the concepts are very similar.

For more details, see the comments in include/linux/static_call.h.

[peterz: simplified interface; merged trampolines]

Signed-off-by: Josh Poimboeuf <jpoimboe@redhat.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Reviewed-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Link: https://lore.kernel.org/r/20200818135804.684334440@infradead.org

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static_call: Add basic static call infrastructure

Static calls are a replacement for global function pointers. They use
code patching to allow direct calls to be used instead of indirect
calls. Th

static_call: Add basic static call infrastructure

Static calls are a replacement for global function pointers. They use
code patching to allow direct calls to be used instead of indirect
calls. They give the flexibility of function pointers, but with
improved performance. This is especially important for cases where
retpolines would otherwise be used, as retpolines can significantly
impact performance.

The concept and code are an extension of previous work done by Ard
Biesheuvel and Steven Rostedt:

https://lkml.kernel.org/r/20181005081333.15018-1-ard.biesheuvel@linaro.org
https://lkml.kernel.org/r/20181006015110.653946300@goodmis.org

There are two implementations, depending on arch support:

1) out-of-line: patched trampolines (CONFIG_HAVE_STATIC_CALL)
2) basic function pointers

For more details, see the comments in include/linux/static_call.h.

[peterz: simplified interface]

Signed-off-by: Josh Poimboeuf <jpoimboe@redhat.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Reviewed-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Link: https://lore.kernel.org/r/20200818135804.623259796@infradead.org

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lib/vdso: Allow to add architecture-specific vdso data

The initial assumption that all VDSO related data can be completely generic
does not hold. S390 needs architecture specific storage to access t

lib/vdso: Allow to add architecture-specific vdso data

The initial assumption that all VDSO related data can be completely generic
does not hold. S390 needs architecture specific storage to access the clock
steering information.

Add struct arch_vdso_data to the vdso data struct. For architectures which
do not need extra data this defaults to an empty struct. Architectures
which require it, enable CONFIG_ARCH_HAS_VDSO_DATA and provide their
specific struct in asm/vdso/data.h.

Signed-off-by: Sven Schnelle <svens@linux.ibm.com>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Link: https://lkml.kernel.org/r/20200804150124.41692-2-svens@linux.ibm.com

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entry: Provide generic syscall entry functionality

On syscall entry certain work needs to be done:

- Establish state (lockdep, context tracking, tracing)
- Conditional work (ptrace, seccomp,

entry: Provide generic syscall entry functionality

On syscall entry certain work needs to be done:

- Establish state (lockdep, context tracking, tracing)
- Conditional work (ptrace, seccomp, audit...)

This code is needlessly duplicated and different in all
architectures.

Provide a generic version based on the x86 implementation which has all the
RCU and instrumentation bits right.

As interrupt/exception entry from user space needs parts of the same
functionality, provide a function for this as well.

syscall_enter_from_user_mode() and irqentry_enter_from_user_mode() must be
called right after the low level ASM entry. The calling code must be
non-instrumentable. After the functions returns state is correct and the
subsequent functions can be instrumented.

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Acked-by: Kees Cook <keescook@chromium.org>
Link: https://lkml.kernel.org/r/20200722220519.513463269@linutronix.de

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kbuild: remove cc-option test of -fno-stack-protector

Some Makefiles already pass -fno-stack-protector unconditionally.
For example, arch/arm64/kernel/vdso/Makefile, arch/x86/xen/Makefile.

No probl

kbuild: remove cc-option test of -fno-stack-protector

Some Makefiles already pass -fno-stack-protector unconditionally.
For example, arch/arm64/kernel/vdso/Makefile, arch/x86/xen/Makefile.

No problem report so far about hard-coding this option. So, we can
assume all supported compilers know -fno-stack-protector.

GCC 4.8 and Clang support this option (https://godbolt.org/z/_HDGzN)

Get rid of cc-option from -fno-stack-protector.

Remove CONFIG_CC_HAS_STACKPROTECTOR_NONE, which is always 'y'.

Note:
arch/mips/vdso/Makefile adds -fno-stack-protector twice, first
unconditionally, and second conditionally. I removed the second one.

Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>
Reviewed-by: Kees Cook <keescook@chromium.org>
Acked-by: Ard Biesheuvel <ardb@kernel.org>
Reviewed-by: Nick Desaulniers <ndesaulniers@google.com>

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arch: remove HAVE_COPY_THREAD_TLS

All architectures support copy_thread_tls() now, so remove the legacy
copy_thread() function and the HAVE_COPY_THREAD_TLS config option. Everyone
uses the same proc

arch: remove HAVE_COPY_THREAD_TLS

All architectures support copy_thread_tls() now, so remove the legacy
copy_thread() function and the HAVE_COPY_THREAD_TLS config option. Everyone
uses the same process creation calling convention based on
copy_thread_tls() and struct kernel_clone_args. This will make it easier to
maintain the core process creation code under kernel/, simplifies the
callpaths and makes the identical for all architectures.

Cc: linux-arch@vger.kernel.org
Acked-by: Thomas Bogendoerfer <tsbogend@alpha.franken.de>
Acked-by: Greentime Hu <green.hu@gmail.com>
Acked-by: Geert Uytterhoeven <geert@linux-m68k.org>
Reviewed-by: Kees Cook <keescook@chromium.org>
Signed-off-by: Christian Brauner <christian.brauner@ubuntu.com>

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docs: move other kAPI documents to core-api

There are a number of random documents that seem to be
describing some aspects of the core-api. Move them to such
directory, adding them at the core-api/i

docs: move other kAPI documents to core-api

There are a number of random documents that seem to be
describing some aspects of the core-api. Move them to such
directory, adding them at the core-api/index.rst file.

Signed-off-by: Mauro Carvalho Chehab <mchehab+huawei@kernel.org>
Link: https://lore.kernel.org/r/86d979ed183adb76af93a92f20189bccf97f0055.1592918949.git.mchehab+huawei@kernel.org
Signed-off-by: Jonathan Corbet <corbet@lwn.net>

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treewide: replace '---help---' in Kconfig files with 'help'

Since commit 84af7a6194e4 ("checkpatch: kconfig: prefer 'help' over
'---help---'"), the number of '---help---' has been gradually
decreasi

treewide: replace '---help---' in Kconfig files with 'help'

Since commit 84af7a6194e4 ("checkpatch: kconfig: prefer 'help' over
'---help---'"), the number of '---help---' has been gradually
decreasing, but there are still more than 2400 instances.

This commit finishes the conversion. While I touched the lines,
I also fixed the indentation.

There are a variety of indentation styles found.

a) 4 spaces + '---help---'
b) 7 spaces + '---help---'
c) 8 spaces + '---help---'
d) 1 space + 1 tab + '---help---'
e) 1 tab + '---help---' (correct indentation)
f) 1 tab + 1 space + '---help---'
g) 1 tab + 2 spaces + '---help---'

In order to convert all of them to 1 tab + 'help', I ran the
following commend:

$ find . -name 'Kconfig*' | xargs sed -i 's/^[[:space:]]*---help---/\thelp/'

Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>

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scs: Remove references to asm/scs.h from core code

asm/scs.h is no longer needed by the core code, so remove a redundant
header inclusion and update the stale Kconfig text.

Tested-by: Sami Tolvanen

scs: Remove references to asm/scs.h from core code

asm/scs.h is no longer needed by the core code, so remove a redundant
header inclusion and update the stale Kconfig text.

Tested-by: Sami Tolvanen <samitolvanen@google.com>
Reviewed-by: Mark Rutland <mark.rutland@arm.com>
Signed-off-by: Will Deacon <will@kernel.org>

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scs: Disable when function graph tracing is enabled

The graph tracer hooks returns by modifying frame records on the
(regular) stack, but with SCS the return address is taken from the
shadow stack,

scs: Disable when function graph tracing is enabled

The graph tracer hooks returns by modifying frame records on the
(regular) stack, but with SCS the return address is taken from the
shadow stack, and the value in the frame record has no effect. As we
don't currently have a mechanism to determine the corresponding slot
on the shadow stack (and to pass this through the ftrace
infrastructure), for now let's disable SCS when the graph tracer is
enabled.

With SCS the return address is taken from the shadow stack and the
value in the frame record has no effect. The mcount based graph tracer
hooks returns by modifying frame records on the (regular) stack, and
thus is not compatible. The patchable-function-entry graph tracer
used for DYNAMIC_FTRACE_WITH_REGS modifies the LR before it is saved
to the shadow stack, and is compatible.

Modifying the mcount based graph tracer to work with SCS would require
a mechanism to determine the corresponding slot on the shadow stack
(and to pass this through the ftrace infrastructure), and we expect
that everyone will eventually move to the patchable-function-entry
based graph tracer anyway, so for now let's disable SCS when the
mcount-based graph tracer is enabled.

SCS and patchable-function-entry are both supported from LLVM 10.x.

Signed-off-by: Sami Tolvanen <samitolvanen@google.com>
Reviewed-by: Kees Cook <keescook@chromium.org>
Reviewed-by: Mark Rutland <mark.rutland@arm.com>
Signed-off-by: Will Deacon <will@kernel.org>

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scs: Add support for Clang's Shadow Call Stack (SCS)

This change adds generic support for Clang's Shadow Call Stack,
which uses a shadow stack to protect return addresses from being
overwritten by a

scs: Add support for Clang's Shadow Call Stack (SCS)

This change adds generic support for Clang's Shadow Call Stack,
which uses a shadow stack to protect return addresses from being
overwritten by an attacker. Details are available here:

https://clang.llvm.org/docs/ShadowCallStack.html

Note that security guarantees in the kernel differ from the ones
documented for user space. The kernel must store addresses of
shadow stacks in memory, which means an attacker capable reading
and writing arbitrary memory may be able to locate them and hijack
control flow by modifying the stacks.

Signed-off-by: Sami Tolvanen <samitolvanen@google.com>
Reviewed-by: Kees Cook <keescook@chromium.org>
Reviewed-by: Miguel Ojeda <miguel.ojeda.sandonis@gmail.com>
[will: Numerous cosmetic changes]
Signed-off-by: Will Deacon <will@kernel.org>

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clk: Move HAVE_CLK config out of architecture layer

The implementation of 'struct clk' is not really an architectual detail
anymore now that most architectures have migrated to the common clk
framew

clk: Move HAVE_CLK config out of architecture layer

The implementation of 'struct clk' is not really an architectual detail
anymore now that most architectures have migrated to the common clk
framework. To sway new architecture ports away from trying to implement
their own 'struct clk', move the config next to the common clk framework
config.

Cc: Russell King <linux@armlinux.org.uk>
Cc: Arnd Bergmann <arnd@arndb.de>
Signed-off-by: Stephen Boyd <sboyd@kernel.org>
Link: https://lkml.kernel.org/r/20200409064416.83340-11-sboyd@kernel.org
Reviewed-by: Arnd Bergmann <arnd@arndb.de>

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dma-direct: provide a arch_dma_clear_uncached hook

This allows the arch code to reset the page tables to cached access when
freeing a dma coherent allocation that was set to uncached using
arch_dma_

dma-direct: provide a arch_dma_clear_uncached hook

This allows the arch code to reset the page tables to cached access when
freeing a dma coherent allocation that was set to uncached using
arch_dma_set_uncached.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Robin Murphy <robin.murphy@arm.com>

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dma-direct: make uncached_kernel_address more general

Rename the symbol to arch_dma_set_uncached, and pass a size to it as
well as allow an error return. That will allow reusing this hook for
in-pl

dma-direct: make uncached_kernel_address more general

Rename the symbol to arch_dma_set_uncached, and pass a size to it as
well as allow an error return. That will allow reusing this hook for
in-place pagetable remapping.

As the in-place remap doesn't always require an explicit cache flush,
also detangle ARCH_HAS_DMA_PREP_COHERENT from ARCH_HAS_DMA_SET_UNCACHED.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Robin Murphy <robin.murphy@arm.com>

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dma-direct: remove the cached_kernel_address hook

dma-direct now finds the kernel address for coherent allocations based
on the dma address, so the cached_kernel_address hooks is unused and
can be r

dma-direct: remove the cached_kernel_address hook

dma-direct now finds the kernel address for coherent allocations based
on the dma address, so the cached_kernel_address hooks is unused and
can be removed entirely.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Robin Murphy <robin.murphy@arm.com>

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context-tracking: Introduce CONFIG_HAVE_TIF_NOHZ

A few archs (x86, arm, arm64) don't rely anymore on TIF_NOHZ to call
into context tracking on user entry/exit but instead use static keys
(or not) to

context-tracking: Introduce CONFIG_HAVE_TIF_NOHZ

A few archs (x86, arm, arm64) don't rely anymore on TIF_NOHZ to call
into context tracking on user entry/exit but instead use static keys
(or not) to optimize those calls. Ideally every arch should migrate to
that behaviour in the long run.

Settle a config option to let those archs remove their TIF_NOHZ
definitions.

Signed-off-by: Frederic Weisbecker <frederic@kernel.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Andy Lutomirski <luto@kernel.org>
Cc: Russell King <linux@armlinux.org.uk>
Cc: Catalin Marinas <catalin.marinas@arm.com>
Cc: Will Deacon <will@kernel.org>
Cc: Ralf Baechle <ralf@linux-mips.org>
Cc: Paul Burton <paulburton@kernel.org>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Michael Ellerman <mpe@ellerman.id.au>
Cc: David S. Miller <davem@davemloft.net>

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